In conventional tractor-mounted backhoe assemblies, including both those with fixed backhoe pivots and those which are sideshift backhoes, a number of hydraulic lines typically run between the tractor and the hydraulic cylinders of the backhoe to carry hydraulic fluid to and from the cylinders controlling the movable parts of the backhoe. In extending from the hydraulic pumps on the tractor to the cylinders on the backhoe, the hoses must pass by or through a backhoe swing tower which pivots with respect to the tractor, usually by about 180 degrees, to provide the backhoe its range of lateral movement.
A variety of schemes and arrangements have been used to connect hydraulic hoses to movable vehicle-attached implements such as tractors. Specific examples of apparatus of the prior art include the following U.S. Pat. Nos.:
3,082,890 (Van Auwelaer et al.); PA1 3,120,897 (Van Auwelaer et al.); PA1 3,263,839 (Hauff); PA1 3,627,155 (Van Der Zyl); PA1 3,722,916 (Muntjanoff); PA1 4,234,012 (Schupback); PA1 3,236,394 (McMullen); PA1 2,756,039 (Barrett); and PA1 4,557,448 (Brown et al.).
Prior hydraulic hose connection schemes and arrangements have significant problems and disadvantages, primarily relating to excessive hose wear. There are several reasons for these problems, including location of hoses in excessively exposed positions, rubbing of hoses against hard surfaces, rubbing of hoses against adjacent hoses, crowding of hoses into confined spaces, hose contortion, and various combinations of reasons.
Generally speaking, it is desirable for hydraulic hoses to pass through rather than around the swinging interconnection of the backhoe to the tractor, that is, through the backhoe swing tower. This puts the hoses in a generally less exposed position than would otherwise be the case. However, crowding of hoses in the confined space which is typically at the focal point of the swinging implement mount exacerbates hose wear problems.
More specifically, while there is limited space in the swing tower, the multiple functions of the backhoe require that several hydraulic hoses be routed through such tower. Backhoes typically have the need for at least six and frequently a many as eight hydraulic hoses to extend from the tractor to the backhoe, including a pair of hoses for each of the following hydraulic cylinders: a bucket cylinder, a dipper cylinder, a boom cylinder, and in many cases a cylinder for extending the reach of the backhoe. This multiplicity of hoses often causes excessive rubbing and hose wear in one way or another.
If two or more hoses in such confined space are arranged against one another, along parallel, usually horizontal, straight lines at generally the same level and extending generally across the vertical axis defined by the pivoting connection of swing tower to tractor, the sides of such adjacent hoses will often rub together. The swinging of the backhoe from one side to another about the vertical axis tends to cause the inner sides of hoses in the outer position (with respect to the direction of swing) to contact and rub forcefully against the outer sides of hoses in the inner position.
In order to reduce hose wear, one conventional arrangement has horizontally-extending portions of each of the hydraulic hoses stacked in parallel fashion into a single stack which passes through or very near the pivot axis of the swing tower. However, when the pivoting interconnection of backhoe swing tower and tractor tower mount includes two vertically-spaced upper and lower articulations, such vertical hose stacking may not be possible. Or the stacking and the space limitation may in any event result in harmful rubbing and chafing during backhoe swinging.
Such rubbing and wear problems are often made worse because the hydraulic hoses, which are built to handle relatively high pressure, are typically thick rubberized and coated fabrics which are not very compliant. Any twisting of the line and even the bends and directions of the hose beyond the area of the backhoe swing tower have a tendency to cause the hose, as backhoe swings from side to side, to move in unpredictable ways from the intended hose position and orientation. Thus, hoses which are stacked in contact tend to rub one another in ways causing wear.
Various prior art hydraulic hose arrangement schemes have failed to adequately protect hydraulic hoses extending by or through backhoe swing towers against excessive hose wear. Improved apparatus is needed.